🔬Cytomorphology of mixed-phenotype acute leukemia (MPAL). ✅Peripheral blood smear from a patient with two blast populations: A. Most circulating blasts have cytomorphological features of lymphoblasts, including scanty cytoplasm. B. Some of the circulating blasts in this case demonstrate cytomorphological features of promonocytes (blast equivalents) and immature monocytes with indented nuclei and relatively abundant agranular cytoplasm with rare vacuoles.
❗Mixed-phenotype acute leukemia may consist of a single morphological blast population (morphological blasts) but express antigens from two or more lineages. Such blasts are then called biphenotypic. If the blasts consist of two populations, each belonging to different lineages, then they are called bilineal. While these terms are conceptually simple, they can be difficult to apply in practice due to the complexity of antigen expression patterns; fortunately, these terms are not associated with known differences in clinical practice.
👉Source: Classification of hematolymphoid Tumors, WHO 5th edition 2022.
